Structure determination and refinement of human alpha class glutathione transferase A1-1, and a comparison with the Mu and Pi class enzymes.
Sinning, I., Kleywegt, G.J., Cowan, S.W., Reinemer, P., Dirr, H.W., Huber, R., Gilliland, G.L., Armstrong, R.N., Ji, X., Board, P.G., Olin, B., Mannervik, B., Jones, T.A.(1993) J Mol Biol 232: 192-212
- PubMed: 8331657 
- DOI: https://doi.org/10.1006/jmbi.1993.1376
- Primary Citation of Related Structures:  
1GUH - PubMed Abstract: 
The crystal structure of human alpha class glutathione transferase A1-1 has been determined and refined to a resolution of 2.6 A. There are two copies of the dimeric enzyme in the asymmetric unit. Each monomer is built from two domains. A bound inhibitor, S-benzyl-glutathione, is primarily associated with one of these domains via a network of hydrogen bonds and salt-links. In particular, the sulphur atom of the inhibitor forms a hydrogen bond to the hydroxyl group of Tyr9 and the guanido group of Arg15. The benzyl group of the inhibitor is completely buried in a hydrophobic pocket. The structure shows an overall similarity to the mu and pi class enzymes particularly in the glutathione-binding domain". The main difference concerns the extended C terminus of the alpha class enzyme which forms an extra alpha-helix that blocks one entrance to the active site and makes up part of the substrate binding site.
Organizational Affiliation: 
Department of Molecular Biology, Uppsala University Biomedical Center, Sweden.